Practice Essentials

Bacterial endophthalmitis (see the image below) is an inflammatory reaction of the intraocular fluids or tissues caused by microbial organisms. Bacteria may gain entry into the eye via corneal or scleral trauma (surgical or accidental) or hematogenously. If not properly treated, bacterial endophthalmitis can result in complete vision loss and persistent ocular pain.

Diagnosis

Perform culture and sensitivity studies on aqueous and vitreous samples to determine the type of organism and antibiotic sensitivity.
[9, 10] If endogenous bacterial endophthalmitis is suspected, a systemic workup for the source is required, with cultures of blood, sputum, and urine.
[11]

Sampling procedures

Anterior chamber tap

Vitreous tap

Vitreous biopsy: A 23-gauge vitrectomy cutter may be used if available

For anterior chamber taps, a 30-gauge needle on a tuberculin syringe is used to obtain a 0.1-mL sample under topical anesthesia through the limbus. For vitreous taps, a sub-Tenon or retrobulbar block with lidocaine with epinephrine is given, and a 21-gauge needle on a tuberculin syringe is used to obtain an adequate vitreous sample of 0.1-0.2 mL.

B-scan ultrasound

Perform B-scan ultrasound of the posterior pole if view of fundus is poor

Typically, choroidal thickening and ultrasound echoes in the anterior and posterior vitreous support the diagnosis

Occasionally, another source of inflammation other than or in addition to bacteria, such as retained lens material, may be seen

The ultrasound also provides a baseline prior to intraocular intervention and allows assessment of the posterior vitreous face and areas of possible traction
[12]

Rarely, a retinal detachment is seen concurrently with endophthalmitis

Other imaging studies

In traumatic cases, a CT scan may show thickening of the sclera and uveal tissues associated with various degree of increased density in the vitreous and periocular soft tissue structures. For possible endogenous cases, imaging modalities to rule out potential sources of infection include 2-dimensional echocardiography and chest x-ray.

Management

Bacterial endophthalmitis is an ocular emergency, and urgent treatment is required to reduce the potential of significant visual loss.
[13, 14] All patients should have therapy consisting of the following
[15, 16, 17, 18] :

When the inflammation is severe, systemic and periocular therapy may be used in non–cataract-induced, delayed onset, filtering bleb–associated, and posttraumatic endophthalmitis. In endogenous endophthalmitis, systemic, topical, and possibly periocular therapy is usually required.
[8]

Antibiotics

Vancomycin - For patients who cannot receive or have failed to respond to penicillins and cephalosporins or have infections with resistant staphylococci; Assaad et al showed that vancomycin was effective against 99.6% of gram-positive bacterial endophthalmitis isolates tested
[19] ; Ahmed et reported that intravitreal, rather than intravenous, vancomycin is necessary for the treatment of bacterial endophthalmitis.
[20] It is not necessary to monitor vancomycin levels when administered via intravitreal injection.

Pathophysiology

The entry of bacteria into the eye occurs from a breakdown of the ocular barriers. Penetration through the cornea or sclera results in an exogenous insult to the eye. If the entry is through the vascular system, then an endogenous route occurs. After the bacteria gain entry into the eye, rapid proliferation occurs.

The vitreous acts as a superb medium for bacteria growth, and, in the past, animal vitreous was used as a culture medium. Bacteria, as foreign objects, incite an inflammatory response. The cascade of inflammatory products occurs resulting in an increase in the blood-ocular barrier breakdown and an increase in inflammatory cell recruitment. The damage to the eye occurs from the breakdown of the inflammatory cells releasing the digestive enzymes as well as the possible toxins produced by the bacteria. Destruction occurs at all tissue levels that are in contact with the inflammatory cells and toxins.

Previous

Next:

Frequency

United States

Incidence after intraocular surgery is less than 0.1%. Incidence of culture-proven endophthalmitis is similar to that of extracapsular cataract extraction and phacoemulsification.

Europe

Creuzot-Garcher et al report an incidence of postoperative endophthalmitis after stand-alone cataract surgery in France of 0.102%, increasing to 0.149% when cataract surgery was combined with corneal, glaucoma, or vitreoretinal procedures.
[22]

Previous

Next:

Mortality/Morbidity

If not properly treated, a risk of complete vision loss and the possibility of persistent ocular pain exist. Infection very rarely spreads beyond the confines of the sclera and tracks into surrounding tissue structures.

Previous

Next:

Prognosis

The prognosis depends on the following:

Duration of endophthalmitis

Time to treatment

Virulence of bacteria

Etiology of entry

Existing ocular diseases

From the EVS, the percentage of patients achieving a final visual acuity of 20/100 or better were as follows:

The authors and editors of Medscape Reference gratefully acknowledge the contributions of previous coauthors, David T Wong, MD, FRCS(C), and Hesham Lakosha, MBChB, MS, FRCS, to the development and writing of this article.